The present disclosure relates to the field of display technologies, and more particularly, to a display back plate and a fabricating method thereof and a display device.
To enhance a luminance of an organic light-emitting diode (OLED) element in an OLED display device, one means in the prior art is to form a cathode and an anode of the OLED element into a microcavity structure. Referring to FIG. 1, it is a schematic structural diagram of an OLED of an OLED display device in the prior art, including an anode 300 and a cathode 400, a back plate auxiliary layer 200 configured to bear the anode 300, and a pixel defining layer 500 and an electroluminescent material layer 600 which are formed on the anode 300. A plurality of recesses are formed in the pixel defining layer 500, the electroluminescent material layer 600 is formed in each of the recesses, and the cathode 400 is formed on the electroluminescent material layer 600 and the pixel defining layer 500. Corresponding to locations of sub-pixels with different colors (R/G/B), the thickness of the electroluminescent material layer 600 may be different (the longer the wavelength of light of the color of a sub-pixel is, the thicker the electroluminescent material layer 600 at the sub-pixel is), so that at each sub-pixel, the anode 300 and the cathode 400 may constitute a microcavity structure that can enhance light of the color of the sub-pixel. Referring to FIG. 1, supposing that the colors of the sub-pixels are red (R), green (G), and blue (B), the thickness of the electroluminescent material layer 600 formed at the red sub-pixel R is greater than that of the electroluminescent material layer 600 formed at the green sub-pixel G, and the thickness of the electroluminescent material layer 600 formed at the green sub-pixel G is greater than that of the electroluminescent material layer 600 formed at the blue sub-pixel B. In this way, when cathode materials are deposited on the pixel defining layer 500 and the light-emitting material layer 600 to form the cathode 400, the electroluminescent material layer 600 bearing the cathode materials is different in thickness at different sub-pixels, which may cause the cathode materials to be formed on different planes, thereby reducing the film formation quality of the cathode materials and easily causing fracture of the formed cathode layer.